Pit prop



Feb- 27, 1940- w. HlNsELMANN Er 1. 2,192,079

PIT PROP 4 sheets-sheet 1 Filed June l5, 1937 Feb- 27, 1940. w. HlNsELMANN Erm. l y 2,192,079

PITPROP Filed June l5, 1937 4 Sheets-Sheet 2 7Il F193 159:4

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Feb 27, 1949. w. HWSELMANN n A@ 2,192,079

PIT PROP 4 Sheets-Sheet 3 Filed June 15, 1937 Feb- 27 1940- w. HlNsELMANN E-r Al. 2,192,079

PIT PROP Fiied June 15. 1937 4 Sheets-Sheet 4 Fig? Patented F eb. 27, 1940 PATENT OFFICE PIT PROP Wilhelm Hinselmann, Essen-Bredeney, and Carl Tiefenthal, Velbert, Germany Application June 1.5, 1937, Serial No. 148,394

In Germany June 17, 1936 7 Claims.

The invention relates to metal pit props of the kind in which a member with a wedge shaped taper is inserted into a hollow member and made fast by means of a wedge driven besy side it into the hollow member. These props are in some cases under very heavy load, which imposes very high pressure upon the coacting wedge surfaces, and it is important to make these surfaces of a size adequate to distribute 10 the pressure so that binding is prevented.

According to our invention at least one supplementary wedge device is provided, on the opposite side and at a different level, so Vthat the l pressure is distributed over a greater length of 1B the prop. For this purpose the hollow member of the prop may have, in addition to the usual pocket for a wedge, an upwardly tapering wedge shaped extension on the side opposite the pocket, engaging into a pocket formed by part of a collar from which the wedge entering the lfirst mentioned pocket extends downwards.

The several wedge surfaces are at the same angle, with a slope which preferably slightly exceeds the angle of rest, so that the paired wedges are not self-locking.

The invention is illustrated in they accompanying drawings, showing various forms of construction.

Figs. 1 to 3 show one form, Fig. l being a 30, longitudinal section and Figs. 2 and 3 being eleva' tions, viewed from different directions.

Figs. 4, 5 and 6 show another form of construction, Figs. 4 and 6 being elevations Viewed from` different directions, and Fig. 5 being a sectional View.

Fig. '7 is a sectional plan view showing a group of props braced together by means of ties, and

Figs. 8 and 9 are vertical sections showing further forms of construction. 40v Referring rst to the construction shown in Figs. l, 2 and 3, a is an iron tube, into which the upper, downwardly tapered member b of the prop is inserted. A socket c having an internal shoulder Z` is seated upon the upper end of the tube, and is on one side enlarged to form a wedge shaped pocket m. This pocket faces the inclined side of the member b. On the other side the socket has an upward extension n, which is wedge shaped with an upward taper, and is somewhat narrower than the member b. The member b is surrounded by a movable collar c1 having a downwardly tapered, wedge` shaped part nl adapted to enter the pocket m, and anupwardly tapered enlargement 'm1 of its* bore on the other side, adapted to engage the wedge part n.

When the member b has been pressed against the roof timber the collar c1 is forced down so that the wedge nl is driven into thepocket m, and the part m1 engages the wedge n, causing y, the member b to be held fast. A bracket u on 5' the socket c carries a downwardly and inwardly inclined screw o, which is tightened against a sloping portion of the socket to prevent the same from being driven upwards by the downward thrust of the member b. 'Ihis screw can be 10 slackened from time to time, to allow for the settling of the rock.

The member b has a flange q at its lower end, anda screw p projects through the socket c and the wall of the tube a into the upward path of 15' this flange, to prevent complete withdrawal of the member b. A rack r is fixed in a recess on one side of the member b, to facilitate the lifting of this member by means of a lever s, using top tof the wedge u as a fulcrum.

Figs. 4, 5 and 6 show a modification in which the wedge n1 and the part m1 are rotatable about pivots :1: and y respectively, so that they can accommodate themselves to the bearing surfaces ofthe socket if the part c1 is by accident slightly 25"' askew. The parts n and 'n1 are shown as having the same apex angle, as in Figs. 1 to 8, butfthis is not essential with a pivoted member m1.

For locking the collar upon the socket Figs. 4,

5 and 6 yshow an elastic shackle upivotedto 3'0' metal 15211501" Olglle el with a scale marked thereon. 'Ihis scale lies behind the transverse part of the shackle, and enables the extent to which the p-ropv has yielded to be ascertained.

For pressing the member b` against the roof timber when the prop` is being set up a rack bar 45 1 may, as shown in Figs. 4 and 6, be engaged with an abutment r1 on the socket c and pushed upwards through an eye r" on the member b against the under surface of the head of the prop. The member b can then be heaved up by means of a 50 lever s engaging the rack and resting on a boss t on the socket c.

Fig. 7 shows diagrammati-cally, in sectional plan view, a group of four props braced by means of iron bars e arranged to form a square. The 55 sockets c of the hollow members a of the props (the only parts shown in this gure) have bosses d engaging holes in the bars.

Fig. 8 shows a construction which is simple and cheap and is intended more particularly for use in workings where the props are left only for a comparatively short time in position. For locking the collar c1 umn the socket c there is a shackle u which is similar to that described with reference to Figs. 4, 5 and 6 except that it is not elastic and consequently cannot yield without breaking. To prevent risk of such fracture and collapse of the prop under heavy load the hollow part of the prop is made telescopic, and consists of a bottom part a1 and top part a inserted thereinto, with a Wooden pile or buffer f inside the tubular part a1, between the foot of the same and a plate g closing the tubular part a" at the bottom. The pile f may be crushed under excessive load, but is an effective safeguard against collapse. If required it may be weakened by notching it.

Fig. l9 shows a modification in which the part a1 is inside the part a and has at the bottom a flange onrwhich the rim of the part a rests, the wooden pile f being inside the part a1, which is closed at the top. The wooden pile in this case projects from the part al and forms the foot of the prop.

What we claim is:

1. In a pit prop, a tubular member having at one end a socket that is provided at one side with an internal wedge surface and at the opposite side with an extension having an external Wedge surface; a tapered member partially inserted into the socket end of said tubular member; and a wedge device including two wedge members, oneV inserted into said socket to cooperate with the internal Wedge surface thereof and the other cooperating with the external wedge surface of the said extension.

2. In a pit prop, a tubular member having at one end a socket that is provided at one side with an internal wedge surface and at the opposite side with an extension having an external Wedge surface; a tapered member partially insertedinto the socket end of said tubular member; a wedge device including two wedge members, one inserted into said socket to cooperate with the internal wedge surface thereof and the other cooperating with the external wedge surface of the said extension; and means to look said Wedge de-l vice `to said socket.

3. 'In a pit prop, a tubular member having at one end a socket that is provided at one side with an internal wedge surface and at the opposite side with an extension having an external wedge surface; a tapered member partially inserted into the socket end of said tubular member; a wedge device including two wedge members, one inserted into said socket to cooperate with the internal Wedge surface thereof and the other cooperating with the external wedge surface of the said extension; and means including an elastic connection for locking said Wedge device to said socket.

4. In a pit prop,'a tubular member having at one end a socket that is provided at one side with an internal wedge surface and at the opposite side with an extension having an external wedge surface; a tapered member partially inserted into the socket end of said tubular member; and a wedge device comprising a wedge member inserted into said socket to engage saidinternal wedge surface, a second wedge member to engage said external wedge surface, and a collar embracing said tapered member and connecting said wedge members together.

5. In a pit prop, a tubular member having at one end a socket that is provided at one side with an internal wedge surface and at the opposite side with an extension having an eXternal wedge surface; a ktapered member partially inserted into the socket end of said tubular member; a wedge device including two wedge members, one inserted into said socket to cooperf ate with the internal Wedge surface thereof and the other cooperating with the external wedge surface of the said extension, one of said wedge members being movable with respect to the other; and adjustable means to lock said movable wedge member to said extension.

6. In a pit prop, a tubular member having at one end a socket that is provided at one side with an internal wedge surface and at the opposite side with an extension having an external wedge surface; a tapered member partially inserted into the socket end of said tubular member; a wedge device including two wedge members, oney inserted into saidl socket to cooperate with` the internal wedge surface thereof and the other cooperating with the external wedge surface of the said extension, said wedge members being pivotally connected together; and means to adjustably hold one of said wedge members in position so that it can be set to yield to a predetermined load. l y

7. In a pit prop, a tubular member having at one end a socket that is providedat one side with an internal Wedge surface and at the op-v posite side with an extension having an external Wedge surface; a tapered member partially inserted into the socket end of said tubular member; a wedge device including two wedge members, one inserted into said socket to cooper ate with the internal wedge surface thereof and the other cooperating with the external Wedge surface of the said extension; and a rack engaging said tapered member, said tubular member carrying a fulcrum to support a lever for engaging said rack t'o lift said tapered member.

WILHELM HINSELMANN. CARL TIEFENTHAL. 

